Effects of calcium infusion during exercise on bone health in older adults

PTH And Calcium Responses to Exercise in Older Adults Experiment 2 (PACE Sr. 2)

Early Phase 1 Interventional University of Colorado, Denver · NCT02580604

This study tests if giving calcium during exercise helps improve bone health in older adults who are taking medication for their bones.

Quick facts

PhaseEarly Phase 1
Study typeInterventional
Enrollment35 (estimated)
Ages60 Years to 80 Years
SexFemale
SponsorUniversity of Colorado, Denver Academic / other
Locations1 site (Aurora, Colorado)
Trial IDNCT02580604 on ClinicalTrials.gov

What this trial studies

This study investigates how maintaining serum calcium levels during exercise affects bone resorption markers in older adults. Participants aged 60-80 who are taking bisphosphonates will engage in two treadmill walking sessions, one with calcium infusion and the other with saline. Blood samples will be collected to measure levels of C-telopeptide, parathyroid hormone, total calcium, and serum ionized calcium, allowing researchers to assess the impact of calcium on bone activity during exercise.

Who should consider this trial

Good fit: Ideal candidates are healthy adults aged 60-80 who are currently taking bisphosphonate medication.

Not a fit: Patients with severe bone density issues or those on medications affecting bone metabolism may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved strategies for preventing bone loss in older adults during physical activity.

How similar studies have performed: While there is ongoing research in this area, this specific approach using a calcium clamp during exercise is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Healthy adults aged 60-80 y
* Currently taking a bisphosphonate medication

Exclusion Criteria:

* Use of medications (other than bisphosphonates) in the past 6 months known to affect bone metabolism (e.g., thiazide diuretics, oral glucocorticoids)
* Bone Mineral Density (BMD) t score \< -3.0 at the total hip or lumbar spine
* Known disease or condition associated with intestinal malabsorption
* Moderate or severe renal impairment defined as an estimated glomerular filtration rate of \<60 mL/min/1.73m2 based on the Modified Diet in Renal Disease (MDRD) equation
* Chronic hepatobiliary disease, defined as liver function tests (AST, ALT) \>1.5 times the upper limit of normal; if such values are obtained on initial screening and thought to be transient in nature, repeated testing will be allowed
* Thyroid dysfunction, defined as an ultrasensitive TSH \<0.5 or \>5.0 mU/L; volunteers with abnormal TSH values will be re-considered for participation in the study after follow-up evaluation by the PCP with initiation or adjustment of thyroid hormone replacement
* Serum calcium \<8.5 or \>10.3 mg/dL Serum 25(OH)D \<20 ng/mL; volunteers with abnormal serum 25(OH)D values may be re-considered for participation in the study if serum 25(OH)D is \>20 ng/mL after vitamin D supplementation
* Uncontrolled hypertension defined as resting systolic BP \>150 mmHg or diastolic BP\>90 mmHg; participants who do not meet these criteria at first screening will be re-evaluated, including after follow-up evaluation by the PCP with initiation or adjustment of anti-hypertensive medications
* History of type 1 or type 2 diabetes
* Cardiovascular disease; subjective or objective indicators of ischemic heart disease (e.g., angina, ST segment depression) or serious arrhythmias at rest or during the graded exercise test (GXT) without follow-up evaluation will be cause for exclusion; follow-up evaluation must include diagnostic testing (e.g., stress echocardiogram or thallium stress test) with interpretation by a cardiologist
* Diagnosis or history of asthma

Where this trial is running

Aurora, Colorado

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Osteoporosis
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.